1. Field of the Invention
The present invention relates to a method for connecting terminals of heat seal film substrate used when connecting fine pitch terminals in liquid crystal display device or the like.
2. Description of the Related Art
In a terminal connecting method a method called carbon hot melt for printing a carbon hot melt agent on a terminal of a circuit made of a conductive material is formed on a base film, and thermo-compression bonding, and a method called ANISO type for printing an anisotropic film mixing nickel particles directly on a heat seal film, and thermo-compression bonding are known. In the connection of heat seal film substrate by such methods, however, when the pitches are made fine so as to be applicable to the latest liquid crystal display devices, fluctuations are likely to occur in the contact resistance value or insulation resistance value, and adverse effects may be caused on the functions of the products applied, and accordingly, hitherto, the heat seal film substrate used in liquid crystal display device or the like was of so-called MONOSO type as shown in FIG. 1, in which an anisotropic film 5 mixing nickel particles 5a is printed only on terminals 3 of the circuit printed of a conductive material of silver carbon on a base film 2 of polyimide or polyester, and then a hot melt agent 6 is printed on the surface, and thermo-compression bonded. FIG. 2 is a sectional view showing the state of the terminals 3 on the heat seal film substrate 1 connected to a conductive pattern 9 formed on an insulator 8 of a printed wiring board 7.
In the connection of heat seal film substrate of such conventional MONOSO type, the terminals of the heat seal film substrate side have a height of about 20 .mu.m, and the conductor pattern of the printed wiring board side to which the terminals are connected is about 50 .mu.m high, and therefore the terminals may slip in between the conductor patterns at the time of bonding, and the base film may be elongated by bonding temperature (about 180.degree. C.), and position deviation may occur to make imperfect the connection between the terminals and conductor patterns.